• Transactions of Materials Processing
• /
• v.25 no.1
• /
• pp.56-60
• /
• 2016

Precise prediction and control of the strip profile is crucial for automatic process set-up and operation of a hot strip mill. In the current study, we present the effect of post-deformation on the steady-state strip profile. The process was simulated by a 3-D elastic-plastic finite element (FE) analysis. Comparisons are made between the strip profile measured at the roll exit and the steady-state strip profile. The results raised an issue with regard to the importance of taking into account the effect of post-deformation.

• Transactions of Materials Processing
• /
• v.10 no.2
• /
• pp.130-136
• /
• 2001

The mathematical set-up model was developed to reduce the mechanical property deviation in annealed and slightly rolled steel strip. The mechanical peculiarities of skin pass rolling process, such as high friction value and non-circular contact arc, low reduction and non-negligible entry and exit elastic zones as well as central restricted deformation zone are all taken into account. The deformation of work rolls is calculated with the influence function method and arbitrary contact arc shape is permitted. The strip deformation is modeled by slab method and the entry and exit elastic deformation zones are included. The strip restricted deformation zone near the neutral point is also considered. It was revealed that the new model has better accuracy than present regression model by statistical analysis with actual mill rolling data.

• Journal of Mechanical Science and Technology
• /
• v.15 no.1
• /
• pp.61-65
• /
• 2001

Using the theory of linear piezoelectricity, the problem of two layered strip with a piezoelectric ceramic bonded to an elastic material containing a finite interface crack is considered. The out-of-plane mechanical and in-plane electrical loadings are simultaneously applied to the strip. Fourier transforms are used to reduce the problem to a pair of dual integral equations, which is then expressed in terms of a Fredholm integral equation of the second kind. The stress intensity factor is determined, and numerical analyses for several materials are performed and discussed.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.20 no.7
• /
• pp.2257-2265
• /
• 1996

In the cold rolling mill, it is very important that a constrained static flow stress of rolled strip and rolling force calculation model be exactly considered to improve an prediction accuracy for rolling forces. Therefore, in this study, the values of the constrained static flow stress are used by deriving the regression equation which is a function of rolling conditions(FDT, CT) and chemical compositions(C, Si, Mn), previously applied by making the tables of yield strength for hot coils with size. And with the consideration that an elastic deformation part of an rolled strip appears at the entry and delivery side of the contacting area between the work roll and rolled strip is calculated. By applying these methods, the more accurate prediction for rolling force is obtained. As a results, the deviation of thickness is significantly reduced in the rolling direction.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.8
• /
• pp.855-861
• /
• 2011

We predict the rolled-strip profile for a 6-high mill using thin rolling theory and a numerical model. In the numerical model, we calculate the distributions of the contact pressures between the rolls and the rolling pressure between the strip and the work roll in the transverse direction using the geometric structure of the 6-high mill and the boundary conditions. We determine the distribution of the rolling pressure in the rolling direction via a thin-foil rolling model using Fleck's theory. We calculate the three-dimensional elastic deformation of the work roll using the pressures of the width and rolling directions. We then obtain the three-dimensional strip profile via the elastic deformation of the work roll during the rolling process. The profile is verified by a thin cold-rolling test and FE simulation.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.8 no.4
• /
• pp.129-135
• /
• 2009

In this paper, a finite element model is presented for the prediction of roll force and strip thickness in a backup-roll-drive mill. The proposed FE model is focused mainly on analyzing the elastic/plastic behavior between a work roll and a strip as well as the rigid/plastic behavior between a backup roll and a work roll. The capability of the proposed model is demonstrated through application to 4-high silicon steel rolling mill at POSCO. Results show that the predicted roll force and strip thickness rolled accurately agree with the measured them. It is also illustrated that the proper position of work roll displaced to one side from the vertical centerline of the backup-roll may be determined by minimizing the horizontal force of work roll.

• Structural Engineering and Mechanics
• /
• v.30 no.5
• /
• pp.647-650
• /
• 2008

• Journal of the Korean Magnetics Society
• /
• v.8 no.4
• /
• pp.185-191
• /
• 1998

Magnetic domain structure and static magnetic properties were investigated in the ultra thin 3%Si-Fe strip wound cores when the strips were wound and annealed to relief the stress. The elastic and plastic deformation due to the radius of curvature was also investigated for the cores. At the as-wound state, the maze pattern domain structure was generated on the concave surface of the core and 180$^{\circ}$ domain wall was recovered by annealing 600 $^{\circ}C$$\times$30 min. After annealed by 900 $^{\circ}C$$\times$30 min, Hc of strip-wound cores was not reached to the $H_c$ of the strip even at the cores of elastic deformation region. It is necessary to relief the local stress remained in the core when the cores were manufactured for the application of ultra-thin 3%Si-Fe strip.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.11
• /
• pp.2466-2473
• /
• 2002

In twin roll strip casting process, the design of casting roll is the most important equipment for producing strip. Analyses of heat transfer and deformation for the casting roll are carried out by using the finite element program, ANSYS. Both the elastic deformation and the elasto-plastic deformation under a thermal load are considered in the analysis. Optimization to minimize the volume of roll is performed under the various thermal loads such as the heat flux and the roll speed. Design variables are defined by diameters and positions of the cooling hole in the roll , Although the thermal load remarkably varies, the design variables and objective function are found to be consistent.

• Geomechanics and Engineering
• /
• v.16 no.2
• /
• pp.151-157
• /
• 2018

The constrained conditions of roof and floor for the coal pillar affect the strength of coal pillar very seriously. To analyze the influence of rock mass for the roof and floor on the stability of coal pillar comprehensively, one method based on the mechanical method for the composite rock mass was proposed. In this method, the three rock layers of roof, floor and coal pillar are taken as the bedded composite rock mass. And the influence of rock mass for the roof and floor on the elastic core of coal pillar has been analyzed. This method can obtain not only the derived stress by the cohesive constraining forces for the coal pillar, but also the derived stress for the rock mass of the roof and floor. Moreover, the effect of different mechanical parameters for the roof and floor on the stability of coal pillar have been analyzed systematically. This method can not only analyze the stability of strip coal pillar, but also analyze the stability of other mining pillars whose stress distribution is similar with that of the strip coal pillar.